Overheating Rayburn

[Burnerman]

Further to the nightmare that is persuing me.....
This oil fired Rayburn has a boiler overheat sensor on its front panel. It keeps tripping out, and unfortunately has to be manually reset.
I thought, with all the radiators fully on the hot water produced would be dispersed, no problem. However, it still trips out.
There is no air in the system that I can find. All the rads get hot - some more than others, but they are all new - and all but 2 rads have TRV's.
I can't access the pump - its below a timber floor covered with quarry tiles I have no idea if a bypass is fitted - again, no access. I can't measure the boiler output / input pipe temperature as they are hidden within the kitchen walls somewhere. All I can do is to turn the main boiler stat down to half - and see what happens.
WHAT CAN I DO NOW?? Please, any tips / thoughts /ideas!
Cheers John

 

[doitall]

Dig the floor up and find the pump

 

[Burnerman]

With the intention of.....speeding it up?
If it has to come to that, so be it! Is that what you had in mind?
Cheers John

 

[doitall]

Not particularly, but you're going to need to some when in the future.

If I was having a stab in the dark I would replace the overheat stat.

 

[Burnerman]

Yes, I appreciate that the pump will have to be exposed at some time....however at the moment I just want to get things as good as possible because the house is due to be let.
I thought about renewing the overheat stat but to be fair the thing seems to be ok when I've got the boiler stat turned to half way. I also appreciate that the system needs balancing but when I have a go at this the stat seems to trip things out after a while and its back to square 1. This has clearly been an issue for some time as the pip that you press to reset has a well chewed up tip!
Cheers John

 

[oilman]

Yes, I appreciate that the pump will have to be exposed at some time....however at the moment I just want to get things as good as possible because the house is due to be let.

In that case it is even more important to get the problem sorted. A rented house with a disgruntled tenant is a millstone.

Have you measured the temperature in the location of the thermostat? That will indicate if it is an overheat problem or a faulty stst.

 

[Burnerman]

Its not my house, but one belonging to some friends that I will be caretaking for them - it should fetch £950 pcm rental
The stat phials (3 of them) are just poked into a tube housing near the top of the burner box - if I can find the spec of the overheat sensor I will indeed do what you say. Many thanks for that one! Cheers John

 

[Tipper]

I spent many (un)happy hours fault finding on Rayburns and I'm sorry to say they live in a world of their own!

The development of Rayburn's control systems seem to follow ribbon development, they change something during design to cure a problem and cause another one, etc, etc, and on and on.

There is no logic and most have been installed by those that should know better and boxed in by idiot kitchen fitters so you can't get to the service or repair parts.

Sorry, this will be a long and difficult relationship.....not to mention expensive!

 

[Boilerman2]

Burnerman where do you find all these P**y Cookers iv'e said before avoid them like the Plague they are all a heap of crap, the only cookers I service are Oil Aga's , Redfyres and Nobels with vapourising sleeve burners, I avoid PJ cookers especilaly Rayburns and Stanleys.. life's too short!

 

[outinthestix]

It may need the combustion chamber and heat exchanger and flue ways cleaning. Also if the insulation in the cooker side comb. chamber is holed/collapsed it will cause it to overheat when both burners are on. If you get them cleaned be careful not to put a hole in the insulation.

 

[Burnerman]

Burnerman where do you find all these P**y Cookers iv'e said before avoid them like the Plague they are all a heap of crap, the only cookers I service are Oil Aga's , Redfyres and Nobels with vapourising sleeve burners, I avoid PJ cookers especilaly Rayburns and Stanleys.. life's too short!

This one does seem to haunt me....trouble is, the owners are friends of mine (so far ) and I don't like to be beaten....
I've never had anything to do with vapourising burners, just PJ and the burners themselves aren't an issue - its just the general design of these cookers - if indeed they ever were 'designed' - is truly awful. Anyway, I've got all the rads fully on, and the boiler stat is on half - and it keeps running. For small mercies I'm grateful!
Cheers John

 

[Burnerman]

It may need the combustion chamber and heat exchanger and flue ways cleaning. Also if the insulation in the cooker side comb. chamber is holed/collapsed it will cause it to overheat when both burners are on. If you get them cleaned be careful not to put a hole in the insulation.

This is one of the first things I looked at...the boiler baffles were in a hell of a state and took a lot of getting out. I replaced 2 of them with stainless ones and put them back the correct way.
There was a lot of soot in the flue bottom, where the flue way goes horizontal. Unfortunately there aren't any inspection doors in the flue pipes so I took the whole thing down so I could get in there. The cookerside part is almost unused and the insulation seems good. The boiler was tripping out on its own anyway. So, with new gaskets etc at least the thing is producing heat and not tripping out. As Oilman suggests I think I'll replace the overheat stat anyway as it could be tripping early, I guess. It needs a new Honeywell programmer too - at over £200!
Thanks for your interest! Much appreciated. Cheers John

 

[oilman]

Don't pay that for a programmer, if I recall correctly, the type is a ST6400C, much cheaper, but it's downside is it doesn't have "Rayburn" written on it. I had to replace one in a Rayburn, as somehow the old one melted. You may find both stats are to blame. It's worth testing them properly, otherwise just replace which will save time.

 

[Burnerman]

Don't pay that for a programmer, if I recall correctly, the type is a ST6400C, much cheaper, but it's downside is it doesn't have "Rayburn" written on it. I had to replace one in a Rayburn, as somehow the old one melted. You may find both stats are to blame. It's worth testing them properly, otherwise just replace which will save time.

Thats incredible info and thank you so much for that...is the ST6400c a direct plug in replacement (no wiring diagram to hand)?
Secondly - will the numbers be stamped on the stats (3 of them)?
Cheers again John

 

[oilman]

The ST6400C is the same model but you'll have to use the "HOT WATER" control for the "COOKER" the price difference is around £239-£60=£179. I'd put up with that. You may have a MK1 Rayburn, in which case it's a different model of controller. Post a picture.

There'll probably numbers stamped on the stats, otherwise look here